#include <iostream>
#include <cstdio>
#include <queue>
#include <cstring>
#include <stack>
#include <algorithm>
#define nmx 100005
#define inf 0x3f3f3f3f
using namespace std;

int n, m, niv[nmx], Min[nmx];
vector <int> g[nmx], aux;
vector <vector<int> > R;
stack <int> st;

void afish(int nod, int tata){
    aux.clear();
    while(st.top()!= nod){
        aux.push_back(st.top());
        st.pop();
    }
    st.pop();
    aux.push_back(nod);
    aux.push_back(tata);
    sort(aux.begin(), aux.end());
    R.push_back(aux);
}

void dfs(int nod, int tata){
    niv[nod] = Min[nod] = niv[tata] + 1;
    for(vector<int>::iterator it = g[nod].begin(); it != g[nod].end(); ++it){
        if(*it == tata)
            continue;
        if(not niv[*it]){
            st.push(*it);
            dfs(*it,nod);
            Min[nod] = min(Min[nod],Min[*it]);
            if(Min[*it] >= niv[nod])
                afish(*it,nod);
        }
        else
            Min[nod] = min(Min[nod], niv[*it]);
    }
}

int main(){
    freopen("biconex.in", "r", stdin);
    freopen("biconex.out", "w", stdout);
    scanf("%d %d", &n, &m);
    for(; m; --m){
        int nod1, nod2;
        scanf("%d %d", &nod1, &nod2);
        g[nod1].push_back(nod2);
        g[nod2].push_back(nod1);
    }
    for(int i = 1; i <= n; ++i)
    if(not niv[i]){
        st.push(i);
        dfs(i,0);
        st.pop();
    }
    int x = R.size();
    printf("%d\n", x);
    for(int i = 0; i < x; ++i){
        int y = R[i].size();
        for(int j = 0; j < y; ++j)
            printf("%d ", R[i][j]);
        printf("\n");
    }
    return 0;
}